Methods and apparatus for performing multiple modes of ultrasound imaging using a single ultrasound transducer

ABSTRACT

The present embodiments relate generally to ultrasound imaging methods and apparatus that allow for multiple modes of imaging using a single ultrasound transducer having a plurality of transducer elements. In an embodiment, there is provided an ultrasound imaging machine that is: operable in a first imaging mode in which the plurality of transducer elements are activated; and operable in a second imaging mode different from the first imaging mode, and in the second imaging mode, a subset of the plurality of transducer elements are activated so that ultrasound signals are steered from the subset of the plurality of transducer elements, where any remaining transducer elements of the plurality of transducer elements not part of the subset are inactive when operating in the second imaging mode.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/207,203, filed Jul. 11, 2016. The entire contents of U.S. patentapplication Ser. No. 15/207,203 are hereby incorporated by reference.

FIELD

The present disclosure relates generally to ultrasound imaging, and inparticular, methods and apparatus that enable multiple modes ofultrasound imaging using a single ultrasound transducer.

BACKGROUND

Ultrasound imaging has a wide range of medical applications. Forexample, ultrasound imaging provides a relatively fast and non-invasiveway to assess abdominal organs such as the bladder, liver, uterus,kidneys, and the like. Ultrasound imaging may also be used to obtainimages of the heart.

Traditional ultrasound systems are typically used with a number ofdifferent ultrasound probes that are designed to image different partsof the body. Ultrasound probes (also called ultrasound transducers)generally contain a number of transducer elements that can beselectively pulsed to generated ultrasound signals. These ultrasoundsignals are projected into a volume of tissue and corresponding echosignals are processed to generate an ultrasound image. Different typesof ultrasound probes have different transducer element configurations toallow for imaging different parts of the body.

For example, a phased-array probe typically has a small footprintcontaining a small number of transducer elements positioned on the probehead. The small footprint allows the probe to be positioned on parts ofthe body that have constricted space. To obtain a sufficiently widefield of view using the small number of transducer elements on the probehead, the ultrasound signals are steered in many different directionsduring multiple phases when projected into the volume of tissue beingimaged. The phased multi-directional steering of a phased-array probemakes it suitable for imaging the heart because the ultrasound signalscan be projected through the intercostal space in between a patient'sribs.

In another example, a sequential curvilinear-array probe (also called aconvex or curved probe) contains a larger footprint with a higher numberof transducer elements on the probe head. The higher number oftransducer elements allow for ultrasound signals to be sequentiallyprojected from different portions of a larger surface area on the probehead, so that an ultrasound image can be obtained without the ultrasoundsignals having to be steered in many different directions to obtain adesired field of view. As compared with a phased-array probe, use of asequential curvilinear-array probe with a higher number of transducerelements can allow a larger volume of tissue to be imaged. Where thereare no constricted spaces or anatomical structures (e.g., ribs) thatwould make it difficult to image a particular organ, ultrasoundoperators may generally prefer to use a probe with a larger surface areaso as to obtain the widest field of view. For example, sequentialcurvilinear-array probes are conventionally used to image the abdomen.

When examining a patient, an ultrasound operator may need to switchprobes during the examination in order to complete the examination(e.g., to examine the heart with a phased-array probe, and the abdomenwith a sequential curvilinear-array probe). Switching probes typicallyinvolves physically removing one probe from an ultrasound machine,plugging in a different probe, and operating one or more controls on theultrasound machine to cause the ultrasound machine to operate in thedesired imaging mode that works with the newly-attached probe. This canbe time consuming, and can present problems in certain medicalenvironments such as critical emergency care.

Additionally, it is generally desirable to cover a probe with a sterilecover to protect patients from contamination. This step of adding asterile cover increases the time needed to change probes and may furtherdelay an examination.

There is a need for improved methods and apparatus for imaging differentareas of a patient without the need to switch between different probes.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting examples of various embodiments of the present disclosurewill next be described in relation to the drawings, in which:

FIG. 1 shows a number of example traditional ultrasound transducer typesand the corresponding generated images;

FIG. 2 shows a sequential curvilinear-array transducer operating in aconventional manner to perform imaging;

FIG. 3 shows at least some limitations of a sequential curvilinear-arraytransducer operating in a conventional manner;

FIG. 4 shows a phased-array transducer operating in a conventionalmanner to perform imaging;

FIG. 5 shows at least some limitations of a phased-array transduceroperating in a conventional manner;

FIG. 6 shows a multi-mode curvilinear-array transducer configured toperform imaging in a manner similar to a phased-array transducer, inaccordance with at least one embodiment of the present invention;

FIG. 7 shows a multi-mode linear-array transducer configured to performimaging in a manner similar a phased-array transducer, in accordancewith at least one embodiment of the present invention;

FIG. 8 shows the time delays and apertures used to perform beamformingwhen a multi-mode curvilinear-array transducer is operated in the firstimaging mode, in accordance with at least one embodiment of the presentinvention;

FIG. 9 shows the time delays and apertures used to perform beamformingwhen a multi-mode curvilinear-array transducer is configured to performimaging in the second imaging mode, in accordance with at least oneembodiment of the present invention;

FIG. 10 shows an example configuration of the transducer elementsprovided on a multi-mode curvilinear-array transducer, in accordancewith at least one embodiment of the present invention;

FIG. 11 shows an example configuration of the transducer elementsprovided on a multi-mode linear-array transducer, in accordance with atleast one embodiment of the present invention; and

FIG. 12 shows a functional block diagram of an ultrasound machine, inaccordance with at least one embodiment of the present invention.

DETAILED DESCRIPTION

In a first broad aspect of the present disclosure, there is provided anultrasound imaging method that involves an ultrasound imaging machine:imaging in a first mode using a sequential transducer including aplurality of transducer elements, wherein when imaging in the firstmode, the plurality of transducer elements are activated; and imaging ina second mode different from the first mode, wherein when imaging in thesecond mode, a subset of the plurality of transducer elements areactivated and a plurality of ultrasound signals are steered from thesubset of the plurality of transducer elements, and wherein anyremaining transducer elements of the plurality of transducer elementsnot part of the subset are inactive when imaging in the second mode.

In some embodiments, the imaging in the first mode further includespulsing groups of adjacent transducer elements of the plurality oftransducer elements in a sequential manner, and the imaging in thesecond mode further includes pulsing the subset of the plurality oftransducer elements in a phased manner to generate the plurality ofultrasound signals.

In some embodiments, when imaging in the first mode, the pulsing of thegroups of adjacent transducer elements is performed for the purpose ofbeamforming, and the groups of adjacent transducer elements correspondto respective different apertures along a head of the sequentialtransducer. In some embodiments, when imaging in the second mode, thepulsing of the subset of the plurality of transducer elements in aphased manner is performed for the purpose of beamforming through asingle aperture on the head of the sequential transducer.

In some embodiments, the beamforming performed when imaging in the firstmode includes delayed activation of the transducer elements within eachof the groups of adjacent transducer elements, and a same time delay isused for all the groups of adjacent transducer elements corresponding tothe respective different apertures along the head of the sequentialtransducer. In some embodiments, the beamforming performed when imagingin the second mode includes delayed activation of the transducerelements within the subset of transducer elements, and the beamformingis repeatedly performed on the subset of transducer elements using aplurality of different time delays to steer the plurality of ultrasoundsignals from the single aperture on the head of the sequentialtransducer.

In some embodiments, when imaging in the second mode, each of theplurality of ultrasound signals is steered in a respective differentdirection so that a sector image is generated. In some embodiments, thesector image has a sector angle of 60 to 90 degrees. In someembodiments, angular spacing between the respective different directionsis between 0.35 to 0.70 degrees.

In some embodiments, the sequential transducer is a curvilinear-arraytransducer, and the plurality of transducer elements are arranged alongan arc having a radius of curvature. In some embodiments, the radius ofcurvature is between 30 to 120 millimeters.

In some embodiments, the sequential transducer is a linear-arraytransducer, and the plurality of transducer elements are arranged in aline.

In some embodiments, the plurality of transducer elements have a pitchspacing between each adjacent transducer element, and the pitch spacingis between 100 to 400 microns.

In some embodiments, the plurality of transducer elements have at least128 transducer elements and the subset of the plurality of transducerelements include 16 to 96 of the at least 128 transducer elements.

In some embodiments, the ultrasound imaging machine is provided in aform factor that has a mass less than 4.5 kilograms.

In another broad aspect of the present disclosure, there is provided anultrasound imaging machine including: an ultrasound processor; and asequential transducer communicably coupled to the ultrasound processor,the sequential transducer including a plurality of transducer elements.The ultrasound imaging machine is: operable in a first imaging mode inwhich the ultrasound processor activates the plurality of transducerelements; and operable in a second imaging mode different from the firstimaging mode, and in the second imaging mode, the ultrasound processoractivates a subset of the plurality of transducer elements so that aplurality of ultrasound signals are steered from the subset of theplurality of transducer elements, wherein any remaining transducerelements of the plurality of transducer elements not part of the subsetare inactive when operating in the second imaging mode.

In some embodiments, when operating in the first imaging mode, theultrasound processor is configured to pulse groups of adjacenttransducer elements of the plurality of transducer elements in asequential manner, and when operating in the second imaging mode, theultrasound processor is further configured to pulse the subset of theplurality of transducer elements in a phased manner to generate theplurality of ultrasound signals.

In some embodiments, when operating in the first imaging mode, thepulsing of the groups of adjacent transducer elements is performed forthe purpose of beamforming, and the groups of adjacent transducerelements correspond to respective different apertures along a head ofthe sequential transducer. In some embodiments, when operating in thesecond imaging mode, the pulsing of the subset of the plurality oftransducer elements in a phased manner is performed for the purpose ofbeamforming through a single aperture on the head of the sequentialtransducer.

In some embodiments, the beamforming performed when in the first imagingmode includes delayed activation of the transducer elements within eachof the groups of adjacent transducer elements, and a same time delay isused for all the groups of adjacent transducer elements corresponding tothe respective different apertures along the head of the sequentialtransducer. In some embodiments, the beamforming performed when in thesecond imaging mode includes delayed activation of the transducerelements within the subset of transducer elements, and the beamformingis repeatedly performed on the subset of transducer elements using aplurality of different time delays to steer the plurality of ultrasoundsignals from the single aperture on the head of the sequentialtransducer.

In some embodiments, each of the plurality of ultrasound signals issteered in a respective different direction, so that a sector image isgenerated. In some embodiments, the sector image has a sector angle of60 to 90 degrees. In some embodiments, angular spacing between therespective different directions is between 0.35 to 0.70 degrees.

In some embodiments, the sequential transducer includes a curvilineartransducer, and the plurality of transducer elements are arranged alongan arc having a radius of curvature. In some embodiments, the radius ofcurvature is between 30 to 120 millimeters.

In some embodiments, the sequential transducer is a linear-arraytransducer, and the plurality of transducer elements are arranged in aline.

In some embodiments, the plurality of transducer elements have a pitchspacing between each adjacent transducer element, and the pitch spacingis between 100 to 400 microns.

In some embodiments, the plurality of transducer elements includes atleast 128 transducer elements and the subset of the plurality oftransducer elements includes 16 to 96 of the at least 128 transducerelements.

In some embodiments, the sequential transducer includes a housingcontaining the plurality of transducer elements, and the housingincludes a marking indicating a position of the subset of the pluralityof transducer elements amongst the plurality of transducer elements.

In some embodiments, the ultrasound imaging machine is provided in aform factor that has a mass less than 4.5 kilograms.

In another broad aspect of the present disclosure, there is provided asequential ultrasound transducer, capable of being communicably coupledto an ultrasound processor. The sequential ultrasound transducerincludes: a plurality of transducer elements, wherein when thesequential ultrasound transducer is communicably coupled to theultrasound processor, the ultrasound processor is configured to:activate the plurality of transducer elements in a first imaging mode;and activate a subset of the plurality of transducer elements in asecond imaging mode that is different from the first imaging mode,wherein in the second imaging mode, the ultrasound processor steers aplurality of ultrasound signals from the subset of the plurality oftransducer elements, and wherein any remaining transducer elements ofthe plurality of transducer elements not part of the subset areinactive, when in the second imaging mode.

In another broad aspect of the present disclosure, there is provided amulti-mode ultrasound imaging machine that has different operationalmodes which permit using the same ultrasound probe having the sametransducer element array for multiple purposes. In one embodiment, thesame transducer is used in both a steered imaging mode and a non-steeredimaging mode. The non-steered imaging mode may be used, for example, toimage abdominal organs. The steered imaging mode may be used, forexample, to image a heart.

For simplicity and clarity of illustration, where consideredappropriate, reference numerals may be repeated among the figures toindicate corresponding or analogous elements or steps. In addition,numerous specific details are set forth in order to provide a thoroughunderstanding of the exemplary embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein may be practiced without these specificdetails. In other instances, certain steps, signals, protocols,software, hardware, networking infrastructure, circuits, structures,techniques, well-known methods, procedures and components have not beendescribed or shown in detail in order not to obscure the embodimentsgenerally described herein.

Furthermore, this description is not to be considered as limiting thescope of the embodiments described herein in any way. It should beunderstood that the detailed description, while indicating specificembodiments, are given by way of illustration only, since variouschanges and modifications within the scope of the disclosure will becomeapparent to those skilled in the art from this detailed description.Accordingly, the specification and drawings are to be regarded in anillustrative, rather than a restrictive, sense.

Referring to FIG. 1, shown there generally as 100 are a number ofexample traditional ultrasound transducer types and the correspondinggenerated image types. As illustrated, a phased-array transducer 102, asequential linear-array transducer 104, and a sequentialcurvilinear-array transducer 106 are shown. Their respectivecorresponding image types 112, 114, 116 are also shown.

A phased-array transducer 102 traditionally has a transducer head with asmall footprint having a small number of transducer elements positionedthereon. Due to the limited number of transducer elements, theultrasound signals 110 are projected in a phased manner in multipledirections to obtain a broader field of view. This results in afan-shape sector image 112 being generated.

A sequential linear-array transducer 104 has a transducer head with alarger footprint on which a larger number of transducer elements arepositioned in a line. Using the larger number of transducer elements,beamforming is performed on successive groups of adjacent transducerelements to direct ultrasound signals 110 into a volume of tissue beingimaged. The ultrasound signals 110 are projected in a single directionorthogonal to the surface of the transducer head. Each projectedultrasound signal 110 forms a scanline, so that the cumulative scanlinesform a rectangular ultrasound image 114.

A sequential curvilinear-array transducer 106 is similar to a sequentiallinear-array transducer 106 in that the transducer head has a largerfootprint with a larger number of transducer elements than aphased-array transducer 102. However, instead of the transducer elementsbeing positioned along a straight line, they are positioned along acurved arc. The ultrasound signals 110 directed from the transducerelements are projected in the same manner as in the sequentiallinear-array transducer (e.g., in a single direction orthogonal to thesurface of the transducer). The placement of the transducer elementsalong the arc allows for a wider field of view, as is shown by thecorresponding generated image type 116.

The image type 116 will have curved portions at both its top and bottomedges. In contrast, while the sector image type 112 generated by thephased-array transducer 102 also has a curved portion at its bottomedge, it's upper edge is a single point because the ultrasound signals110 originate from a single location on the transducer head of thephased-array transducer 102.

The nature of how each transducer type operates may impact the qualityof the image being acquired. For example, referring still to FIG. 1,because the phased-array transducer 102 directs ultrasound signals 110in multiple directions from a small number of transducer elements, thedistance 122 between each scanline increases as the distance from thetransducer head increases. This may reduce the lateral resolution in thefar field of the sector image 122 generated (e.g., the ability toresolve between two adjacent objects in a direction perpendicular to thedirection of beam travel, but in-plane with the ultrasound imaging beinggenerated).

In contrast, since the sequential linear-array transducer 104 projectsparallel ultrasound signals 110 from multiple locations on thetransducer head, there is a consistent distance 124 between adjacentultrasound signals 110 in both the near field and the far field of thegenerated rectangular image 114. As a result, images generated using thesequential linear-array transducer 104 may not suffer from thedegradation in lateral resolution present in sector images 112.

A sequential curved transducer 106 projects ultrasound signals 110 inmultiple diverging directions from its curved transducer head. However,because the ultrasound signals 110 originate from multiple spots along acurved larger transducer head than the phased-array transducer 102, thedistance 126 between adjacent scanlines to not diverge as significantly.As a result, the sequential curved transducer 106 has better lateralresolution in the far field than the phased-array transducer 102.

Transducer elements that operate at a high frequency (e.g., 5-12 MHz)provide better axial resolution (e.g., ability to resolve between twoadjacent objects along the axis of the ultrasound signal's 110 directionof travel) than transducer elements that operate at a low frequency(e.g., 1-4 MHz). High-frequency ultrasound signals 110, however, are notable to penetrate as deep into the body as lower-frequency ultrasoundsignals. As a result, high-frequency transducers are typically used toimage tissue close to the surface of the skin (e.g., blood vessels), andlower-frequency ultrasound signals 110 are typically used to imageinternal organs.

A phased-array transducer 102 is typically provided with transducerelements that operate at a relatively lower frequency (e.g., 1.5-4 MHz).For example, this allows the phased-array transducer 102 to be used toimage the heart. A sequential curved transducer 106 may operate in asimilar frequency range (e.g., 2-5 MHz), so as to allow the sequentialcurvilinear-array transducer 106 to be used for imaging abdominal organssuch as the bladder, liver, uterus, kidneys, and the like.

In contrast, a sequential linear-array transducer 104 may conventionallybe provided with transducer elements that operate at a higher frequency(e.g., 5-12 MHz), as such types of transducers 104 are typically used invascular contexts where the enhanced axial resolution helps resolveblood vessels near the surface of the skin. The enhanced axialresolution of a sequential linear-array transducer 104 may also make itsuitable to be used for other medical procedures near the surface of theskin (e.g., needle guidance).

Table 1 is a chart summarizing characteristics of the example transducertypes shown in FIG. 1:

Sequential Sequential Linear- Curvilinear- Phased-Array Array TransducerArray Transducer 102 104 Transducer 106 Transducer Small Large LargeHead Size Frequency 1.5-4 5-12 2-5 (MHz) Penetration Good Poor GoodAxial Average Very Good Average Resolution Far Field Poor Good AverageLateral Resolution Medical Cardiac, Lung Vascular Abdomen Applications

Conventionally, a single transducer type is associated with a singlemode of operation. There is also a one-to-one mapping between transducertypes 102, 104, 106 and corresponding image types 112, 114, 116. Anultrasound operator may typically select an appropriate transducer type102, 104, 106 based on how a combination of the characteristics of agiven transducer type 102, 104, 106 match the desired medicalapplication.

For example, as noted, it may be preferred to use a sequentialcurvilinear-array transducer 106 to image organs within the abdomenbecause it provides the largest surface area of transducer head, deeppenetration, and acceptable far field lateral resolution. In anotherexample, a phased-array transducer 102 may be used to image the heart orlungs because even though there is poor far field lateral resolution,its small transducer head footprint results in phased multi-directionalultrasound signal 110 projection that allows for imaging through theintercostal space in between a patient's ribs.

As noted, switching between different ultrasound probes during anexamination may be inefficient and cumbersome for an ultrasoundpractitioner. However, as discussed below in relation to FIGS. 2-5,using a single one of the above-noted transducer types to image an areaof the body where another transducer type would be more suitable hasdrawbacks. For example, FIGS. 2-5 compare operation of the phased-arraytransducer 102 and the sequential curvilinear-array transducer 106.Although both transducers 102, 106 are configured with similar operatingfrequencies and can image at similar tissue depths, there arenevertheless drawbacks when any one of the two transducers are used inscenarios where the other transducer type is more appropriate.

Referring to FIG. 2, shown there generally as 200 is a sequential curvedtransducer operating in a conventional manner to perform imaging. Asillustrated, the sequential curvilinear-array transducer 106 projectsultrasound signals 110 into the abdomen. Within the abdomen, there maybe a large organ 210 and a small structure 212 that are within the fieldof view of the sequential curved transducer 106. As shown, due to thewide field of view in both the near field and the far field, asignificant portion of the large organ 210 may be imaged. At the sametime, the average far field resolution of the sequential curvedtransducer 106 may allow the small structure 212 to also be identified.

Referring to FIG. 3, shown there generally as 300 are at least somelimitations of a sequential curved transducer operating in aconventional manner. FIG. 3 illustrates the sequential curvilinear-arraytransducer 106 being applied on an area of a patient's torso where thereare ribs 310 and it is desired to image the organs underneath (e.g., theheart or lungs). The ribs 310, being much denser than the surroundingtissues, reflect ultrasound signals strongly. Since the sequentialcurved ultrasound transducer 106 is configured to project ultrasoundsignals 110 in a direction orthogonal to the surface of the transducerhead, a number of the ultrasound signals 110 are blocked by the ribs310. This creates volumes 320 underneath the ribs 310 that cannot beclearly imaged. Thus, a sequential curvilinear transducer 106 operatedin a conventional manner can generally not acquire good images of theheart or lungs.

Referring to FIG. 4, shown there generally as 400 is a phased-arraytransducer operating in a conventional manner to perform imaging. Due tothe small footprint of the phased-array transducer 102, the ultrasoundsignals 110 are projected in a variety of different directions throughthe space between a patient's ribs 310, so as to allow for imaging oforgans thereunder. As compared to use of a sequential curvilinear-arraytransducer 106 to image the same part of the body (as shown in FIG. 3),it can be seen that use of a phased-array transducer 102 allows forimaging of volumes that would otherwise be difficult to image.

Referring to FIG. 5, shown there generally as 500 are at least somelimitations of a phased-array transducer operating in a conventionalmanner. While it may seem that the phased-array transducer 102 can beused for general-purpose imaging, there are also drawbacks to using thephased-array transducer 102 where a sequential curvilinear-arraytransducer 106 is more appropriate. FIG. 5 shows use of a phased-arraytransducer 102 to image the same volume of the abdomen as was shown inFIG. 2. The volume contains a large organ 210 and a small structure 212.

Although the phased-array transducer 102 may be able to image portionsof the large organ 210, it can be seen that there are volumes 520 (shownin dotted outline) imaged by the curvilinear-array transducer 106 thatare missed by the phased-array transducer 102. This may result in thephased-array transducer 102 not being able to image the large organ 210effectively.

At the same time, due to the poor far field lateral resolution of thephased-array transducer 102, it is possible that imaging using thephased-array transducer 102 may result in the scanlines completelyfailing to identify the small structure 212 in the far field. These areat least two reasons why a traditional phased-array transducer 102 mayperform poorly when imaging in scenarios where a sequentialcurvilinear-array transducer 106 would be more appropriate.

In view of the foregoing, it is apparent that any single existingtraditional transducer type discussed in FIG. 1 may not be able to imagemultiple areas of a patient's torso. However, requiring an ultrasoundoperator to switch between multiple transducer types is also cumbersomeand may be undesirable.

Some existing attempts to address these drawbacks include a dual-headedprobe that allows for different types of scanning from different ends ofthe same probe (e.g., as is available with a product called Vscan withDual Probe™ available from GE Healthcare™). Other existing attemptsinclude configurations with a single probe having interchangeable heads,such that different transducer geometries can be used with the samehandle. However, these attempts still require different heads to be usedfor different types of scanning. The present embodiments may alleviateat least some of the discussed drawbacks in an improved way.

Referring to FIG. 6, shown there generally as 600 is a multi-modecurvilinear-array transducer configured to perform imaging in a mannersimilar to a phased-array transducer, in accordance with at least oneembodiment of the present invention. In the present embodiments, amulti-mode curvilinear-array transducer 606 is configured to operate inat least two modes. In the first mode, the multi-mode curvilinear-arraytransducer 606 operates in the conventional manner. As discussed abovein relation to FIGS. 1 and 2, during operation in this first mode,scanlines (not shown in FIG. 6) may be successively and sequentiallygenerated by pulsing groups of adjacent transducer elements present onthe transducer head 650. These scanlines are created by directing theultrasound signals 110 in a direction orthogonal to the surface of thetransducer head 650. While all of the transducer elements on thetransducer head 650 are typically activated when imaging in the firstmode, in some embodiments, less than all of the transducer elements onthe transducer head 650 may be activated in the first mode.

In the second mode, the multi-mode curvilinear-array transducer 606activates only a subset 654 of the transducer elements that wereactivated in the first imaging mode. At the same time, the ultrasoundsignals 110 projected from this subset 654 of transducer elements aresteered. For example, this may involve the transducer elements in thesubset 654 being pulsed in a phased manner to generate a number ofultrasound signals 110 from the same portion of the transducer head 650.In some embodiments, the steering of the ultrasound signals 110 may bein different directions so that a sector image 112 (as shown in FIG. 1)is generated.

During operation in the second mode, any remaining transducer elements652 not in the subset 654 remain inactive. This is so even if thosetransducer elements would normally be pulsed during the imageacquisition process when a sequential curvilinear-array transducer 106(as shown in FIGS. 1-3) is used in a conventional manner.

By providing a curvilinear-array transducer 606 with a second mode ofoperation that activates only a subset 654 of the available transducerelements and simultaneously steers the ultrasound signals 110 generatedfrom the subset 654 of transducer elements, the multi-modecurvilinear-array transducer 606 may be able to simulate operation of aphased-array transducer 102 (as shown in FIGS. 1, 4, 5). This may allowthe multi-mode curvilinear-array transducer 606 to image volumes oftissue that would otherwise not be viewable using a conventionalsequential curvilinear-array transducer 106.

Shown generally as 600 in FIG. 6, when operated in the second mode, themulti-mode curvilinear-array transducer 606 is able to projectultrasound signals 110 in between the space between ribs 310 to imageorgans such as the heart and lungs. This allows ultrasound operators touse a single transducer to image in situations that typically requiremultiple transducers (e.g., a conventional sequential curvilinear-arraytransducer 106 and a conventional phased-array transducer 102). Themultiple modes of operation may alleviate some of the drawbacksassociated with having to switch transducer probes. For example, use ofa single multi-mode curvilinear-array transducer 606 in situations thattraditionally require multiple transducers may allow for expeditedexaminations during time-sensitive medical applications such asemergency care (e.g., when performing a Focused Assessment withSonography for Trauma, or FAST, examination to assess a patient forinternal bleeding and/or other trauma-related effects).

Shown generally as 601 in FIG. 6 are the image types 112, 116 that canbe obtained using the multi-mode curvilinear-array transducer 606. Asshown, both the conventional field of view image type 116 and a sectorimage type 112 can be obtained using a single multi-modecurvilinear-array transducer 606. Referring briefly to FIG. 1, thiscontrasts with the conventional one-to-one mapping between transducertypes 102, 104, 106 and image types 112, 114, 116.

Referring to FIG. 7, shown there generally as 700 is a multi-modelinear-array transducer configured to perform imaging in a mannersimilar to a phased-array transducer, in accordance with at least oneembodiment of the present invention. As noted above, a conventionalsequential linear-array transducer 104 (as shown in FIG. 1) is typicallyconfigured with transducer elements that operate at a high frequency toprovide better axial resolution in the near field. In some embodimentsof the present disclosure, there is provided a multi-mode linear-arraytransducer 704 that is provided with transducers elements that emitultrasound signals at the same high frequency range that is typicallyemitted by conventional sequential linear-array transducers 104. Similarto the multi-mode curvilinear-array transducer 606 discussed above inrelation to FIG. 6, the multi-mode linear-array transducer 704 may alsobe configured to operate in at least two modes.

In the first mode, the multi-mode linear-array transducer 704 operatesin a manner similar to the conventional operation of a sequentiallinear-array transducer 104. As discussed above in relation to FIG. 1,during operation in this first mode, scanlines may be successively andsequentially generated by pulsing groups of adjacent transducer elementspresent on the transducer head 650′. These scanlines (not shown in FIG.7) are created by directing the ultrasound signals 110 in a directionorthogonal to the linear surface of the transducer head 650′. As was thecase with the multi-mode curvilinear-array transducer 606 of FIG. 6, itmay be possible that all of the transducer elements on the transducerhead 650′ are activated when imaging in the first mode. However, in someembodiments, less than all of the transducer elements on the transducerhead 650′ may be activated in the first mode.

The multi-mode linear-array transducer 704 may be configured to have asecond mode of operation that is similar to the second mode of operationof the multi-mode curvilinear-array transducer 606 discussed in relationto FIG. 6. For example, referring still to FIG. 7, the multi-modelinear-array transducer 704 may activate only a subset 654′ of thetransducer elements that were activated by the transducer 704 in thefirst imaging mode. At the same time, the ultrasound signals 110projected from this subset 654′ of transducer elements can be steered.For example, this may involve the transducer elements in the subset 654′being pulsed in a phased manner to generate a number of ultrasoundsignals 110 from the same portion of the transducer head 650′. In someembodiments, the steering of the ultrasound signals 110 may be indifferent directions so that a sector image 112 is generated.

During operation in the second mode, any remaining transducer elements652′ not in the subset remain inactive. This is so even if thosetransducer elements would normally be pulsed during the imageacquisition process when a sequential linear-array transducer 104 (asshown in FIG. 1) is used in a conventional manner.

By providing a linear-array transducer 704 with a second mode ofoperation that activates only a subset 654′ of the available transducerelements and simultaneously steers the ultrasound signals 110 generatedfrom the subset 654′ of transducer elements, the multi-mode linear-arraytransducer 704 may be able to simulate operation of a phased-arraytransducer that emits high-frequency ultrasound signals 110. This mayallow the multi-mode linear-array transducer 704 to image volumes oftissue that would otherwise not be viewable using a conventionalsequential linear-array transducer 104.

An example scenario where this may be desirable is when the tissue to beimaged is in the near field of the ultrasound image and it is desiredtake advantage of the high axial resolution offered by a conventionalsequential linear-array transducer 104, but where there are structuresobstructing travel of the ultrasound signals 110 near the surface of theskin. The available second mode of operation allows for imaging throughavailable space where the ultrasound signals can 110 travel withoutrequiring an ultrasound operator to switch transducer probes. Forexample, these scenarios may arise in certain pediatric applicationswhere the tissue being imaged is not as deep. Some such pediatricapplications include pediatric cardiac imaging that involves scanningthe heart of children or babies through the space in between a child orbaby's ribs. As with the multi-mode curvilinear-array transducer 606shown in FIG. 6, use of the multi-mode linear-array transducer 704 mayalleviate some drawbacks associated with having to switch transducerprobes.

Shown generally as 701 in FIG. 7 are the image types 112, 114 that canbe obtained using the multi-mode linear-array transducer 704. As shown,it can be seen that both the conventional rectangular image type 114 anda sector image type 112 can be obtained using a single multi-modelinear-array transducer 704. Referring again briefly to FIG. 1, thiscontrasts with the conventional one-to-one mapping between transducertypes 102, 104, 106 and image types 112, 114, 116.

In conventional ultrasound systems, the footprint of a transducer probeselected to be used may generally depend on the physical constraints ofthe medical application. For example, the phased-array probe 102 may beused in situations where physically confined spaces on the patient'sbody does not allow for use of a transducer with a larger footprint. Tothe extent that the medical application allows for imaging with atransducer having a larger footprint that has a correspondingly largernumber of transducer elements, it is generally desired to apply thesequential pulsing technique so as to obtain a larger field of view andavoid the degradation in far field lateral resolution.

However, in the present embodiments, despite the availability ofadditional transducer elements 652, 652′ (as shown in FIGS. 6 and 7)that can be pulsed to generate an ultrasound image, the second mode ofoperation selectively activates only a particular subset 654, 654′ oftransducer elements and steers them to generate a sector image 112. Byconfiguring a transducer with a larger number of transducer elements tooperate in this manner, the multi-mode transducers 606, 704 may be ableto perform additional imaging tasks. While the large footprint of themulti-mode transducers 606, 704 may prevent them from being used in allthe same medical applications as a traditional phased-array transducer102, the multi-mode transducers 606, 704 may still provide improvedimaging functionality (and hence, versatility of examination) overtraditional sequential linear-array transducers 104 and sequentialcurvilinear-array transducers 106.

As discussed above, the multi-mode curvilinear-array transducer 606 isconfigured to operate at relatively low frequencies, whereas themulti-mode linear-array transducer 704 is configured to operate atrelatively high frequencies. However, these are only exampleconfigurations, and the methods and techniques described herein may beapplicable to any type of transducer array that is configured to beactivated in a sequential manner. For example, it may be possible toconfigure a multi-mode linear-array transducer 704 to operate atrelatively low frequencies or a multi-mode curvilinear-array transducer606 to operate at relatively high frequencies.

Referring to FIG. 8, shown there generally as 800 are the time delaysand apertures used to perform beamforming when a multi-modecurvilinear-array transducer 606 (as shown in FIG. 6) is operated in thefirst imaging mode. As discussed above, the first imaging modeconfigures the multi-mode curvilinear-array transducer 606 to operate inmanner similar to the conventional operation of a sequentialcurvilinear-array transducer 106 (as shown in FIGS. 1 and 2). As will beunderstood by persons skilled in the art, beamforming involves applyinga time delay to when adjacent transducer elements 850 are pulsed so thatthe interference pattern generated by ultrasound signals 110 form a beamwhen projected. By varying the time delay and sequence in which thetransducer elements 850 within a group are pulsed, the beam can befocused so that echo signals resulting from the beam are received asreflections from different tissue structures in a volume of interest.

FIG. 8 shows a simplified view of a transducer head 650 with itsconstituent transducer elements 850 and how they are pulsed at threeexample points in time during generation of an ultrasound image. Asdiscussed above, to generate an ultrasound image in conventionaloperation of a sequential transducer, ultrasound beams are transmittedfrom different groups of adjacent transducer elements 850 sequentiallyand successively across the transducer head 650. These ultrasound beamsresult in the formation of scanlines that collectively generate theultrasound image. The position of the transducer elements 850 on thetransducer head 650 where the ultrasound signals get generated may becalled the “aperture”. As will be understood by persons skilled in theart, ultrasound operation may involve a transmit aperture and a receiveaperture. The transmit aperture refers to the transducer elements 850that are activated when the ultrasound signals 110 are generated, andthe receive aperture refers to the transducer elements 850 that receiveecho energy in response. The two apertures may be different such thatthey include different groups of transducer elements 850. Unlessspecifically indicated, the term “aperture” refers to the transmitaperture herein.

At the first point in time, the aperture 804A is on the leftmost portionof the transducer head 650 so that a group of adjacent transducerelements 850 there are pulsed. This group of adjacent transducerelements 850 are pulsed according to a time delay 802A. The time delay802 is illustrated as an arc that represents the sequence of activationwhen the transducers elements 850 are pulsed. As shown, the outermosttransducer elements 850 of the aperture 804A are pulsed first, and thentransducer elements 850 towards the center of the aperture 804A areprogressively pulsed. As will be understood by persons skilled in theart, this type of time delay 802A will generate an ultrasound beam 810Athat focuses in a direction orthogonal to the surface of the transducerhead 650.

At the second point in time, the aperture 804B is in the center portionof the transducer head 650. Since operation of the transducer in thefirst mode causes the ultrasound signal to be projected in a directionorthogonal to the surface of the transducer head 650, the same timedelay 802A is applied to the aperture 804B to generate the ultrasoundbeam 810B.

At the third point in time, the aperture 804C is in the rightmostportion of the transducer head 650. A same time delay 802A is againapplied to generate an ultrasound beam 810C that is perpendicular to thesurface of the transducer head 650 at the position of the aperture 804C.

Referring to FIG. 9, shown there generally as 900 are the time delaysand apertures used to perform beamforming when a multi-modecurvilinear-array transducer 606 (as shown in FIG. 6) is configured toperform imaging in the second imaging mode, in accordance with at leastone embodiment of the present invention.

As discussed above, the second imaging mode configures the multi-modecurvilinear-array transducer 606 to only activate a subset 654 (as shownin FIG. 6) of the transducer elements 850 on the transducer head 650,but at the same time, steer the ultrasound signals 110 generatedtherefrom in multiple directions.

FIG. 9 shows a simplified view of a transducer head 650 with itsconstituent transducer elements 850 and how they are pulsed at threeexample points in time during generation of an ultrasound image duringthe second mode of operation.

At the first point in time, a time delay 802B is applied to an aperture804D on the transducer head 650. Referring simultaneously to FIG. 8, itcan be seen that the shape of the time delay 802B applied is differentfrom the time delay 802A repeatedly applied in FIG. 8. The difference intime delay being applied to the aperture 804D causes the resultantultrasound signal 910A to be steered in a direction that is differentfrom just being orthogonal to the surface of the transducer head 650.Specifically, the particular time delay 802B shown has the rightmosttransducer elements 850 within the aperture 804D being activated firstand then progressively shifting to the left of the aperture 804D in thesequence and manner represented by the time delay 802B. As will beunderstood by persons skilled in the art, the time delay 802B will causethe ultrasound signal 910A to be directed to the left.

At the second point in time, a time delay 802A is applied to the sameaperture 804D that was activated during the first point in time. As canbe seen, this time delay is different from the time delay 802B appliedduring the first point in time. Referring simultaneously to FIG. 8, itcan be seen that the time delay 802A applied at the second point in timein FIG. 9 is substantially similar to the time delay 802A applied atvarious points in time in FIG. 8 to various apertures 804A, 804B, 804C.This is because at the second point in time in FIG. 9, the ultrasoundsignal 910B desired to be projected happens to be orthogonal to thesurface of the transducer head 650.

At the third point in time, a time delay 802C is applied again to thesame aperture 804D that was activated during the first and second pointsin time. The time delay 802C is different from the time delays 802B,802A applied at the first and second points in time. As shown, the timedelay 802C applied is in the reverse sequence and timing to the timedelay 802B applied at the first point in time of FIG. 9. This results inthe ultrasound signal 910C generated being directed to the right.

Referring simultaneously to FIGS. 8 and 9, it can be seen that whenoperating in the first mode (FIG. 8), the multi-mode curvilinear-arraytransducer 606 pulses different apertures 804A, 804B, 804C along thetransducer head 650 with the same time delay 802A so as to causeultrasound signals 810A, 810B 810C to be projected in respectivedirections that are orthogonal to the surface of the transducer head 650at the locations of each aperture 804A, 804B, 804C. In contrast, in thesecond mode (FIG. 9), the multi-mode curvilinear-array transducer 606repeatedly pulses a single aperture 804D on the transducer head 650 butwith different time delays 802B, 802A, 802C to steer the respectiveultrasound signals 910A, 910B, 910C in multiple directions.

Although FIGS. 8 and 9 have been shown and discussed with respect to thetransducer head 650 of the multi-mode curvilinear-array transducer 606originally shown in FIG. 6, the principles of aperture and delayconfiguration can be applied in a similar way to the multi-modelinear-array transducer 704 shown in FIG. 7 to provide the multipleimaging modes discussed herein. In other embodiments, the sameprinciples may be applied to other types of ultrasound probes withtransducer arrays that are conventionally activated in a sequentialmanner.

Referring to FIG. 10, shown there generally as 1000 is an exampleconfiguration of the transducer elements 850 provided on a multi-modecurvilinear-array transducer, in accordance with at least one embodimentof the present invention. As shown, the multi-mode curvilinear-arraytransducer 606 with the transducer head 650 includes its constituenttransducer elements 850. When operated in the second mode, the subset654 of the transducer elements 850 through which the ultrasound signals110 are repeatedly transmitted can be made up of any number oftransducer elements 850. In some embodiments, the transducer head 650may be provided with at least 128 transducer elements 850 that can beactivated during imaging in the first mode. For example, the subset 654of these at least 128 transducer elements 850 that are activated duringimaging in the second mode may include 16 to 96 of the at least 128transducer elements. In a particular example embodiment, the transducerhead may include 192 transducer elements, and the subset 654 of these192 transducer elements may be any one of 16, 32, 64, 80, or 96 of the192 transducer elements.

In some embodiments, when steering the ultrasound signals from thesubset 654 of the transducer elements 850 that are activated in thesecond mode, the angular spacing 1040 between the respective differentdirections in which the ultrasound signals 110 are projected may be inthe range of 0.35 to 0.70 degrees. In an example embodiment, the angularspacing 1040 may be 0.625 degrees.

As noted, the transducer elements 850 of the multi-mode curvilineartransducer 606 can be arranged along an arc having a radius ofcurvature. In various embodiments, the radius of curvature may bebetween 30 to 120 millimeters. In a particular example embodiment, theradius of curvature is 60 millimeters. As compared to a traditionalphased-array transducer 102 that may have an aperture where thetransducer elements 850 are arranged in a line, the time delays 802B,802A, 802C (as shown in FIG. 9) that steer the ultrasound signals 110 inthe second imaging mode may be adjusted to compensate for curvilineararrangement of transducer elements 850. These adjustments may allow atraditional sector image 112 to be generated from a non-linear aperture804D of transducer elements 850.

The construction of the array of transducer elements 850 may impactaspects of an ultrasound image. For example, certain configurations ofthe pitch (centre-to-centre distance between adjacent transducerelements 850) and cut width (the distance between adjacent transducerelements 850) may cause certain types of image artifacts to be morepronounced.

Referring simultaneously to FIG. 1, when traditional ultrasoundtransducer types 102, 104, 106 are designed, these various dimensions ofthe transducer element array may be configured to minimize the presenceof image artifacts in a way that depends on the expected nature of theiroperation (e.g., sequential or phased, as discussed). For example, thetransducer element array of a traditional phased-array transducer 102may be configured to have a pitch of between 150-300 microns and a cutwidth of between 10-150 microns. Since the traditional phased-arraytransducer 102 is designed for acquiring signals by directing ultrasoundsignals 110 in multiple directions, configuring the transducer elementarray in this manner may allow for the ultrasound signals 110 to besteered in a broad range of directions without image artifacts (e.g.,side lobe artifacts) appearing significantly in the resultant sectorimage 112. For example, such a configuration may allow a traditionalsector image 112 to have a sector angle of approximately 90 degrees.

In comparison, the transducer element array of a traditional sequentialcurvilinear-array transducer 106 may be configured to have a pitch ofbetween 200-400 microns and a cut width of between 10-200 microns. Ascompared to the traditional phased-array transducer 102, the differencesin the dimensions of the transducer element array may allow for improvedimaging when imaging in a sequential manner.

Referring back to FIG. 10, the transducer elements 850 of the multi-modecurvilinear transducer 606 in the present embodiments may be configuredto have a pitch of between 100 to 400 microns and a cut width of between10-200 microns. In a specific example embodiment, the pitch is 330microns, and the cut width is 100 microns. This configuration for thetransducer element array is more similar to that of a traditionalsequential curvilinear-array transducer 106 than that of the traditionalphased-array transducer 102, so as to allow for optimal imaging in thesequential manner of the first imaging mode.

However, such a configuration may not be as optimized for phased-arrayimaging as a traditional phased-array transducer 102. For example, insome embodiments, when imaging in the second mode, side lobe artifactsmay appear more pronounced when ultrasound signals are steered in theleftmost and rightmost directions from the center line perpendicular tothe surface of the aperture 804D (as shown in FIG. 9). This is comparedto a traditional phased-array transducer 102, where the appearance ofsuch side lobe artifacts may not be as pronounced. In some embodiments,to minimize the appearance of such side lobe artifacts, the sector angle1046 of the sector image 112 may be reduced from the typical 90-degreesector angle produced by a traditional phased-array transducer 102. Forexample, the sector angle 1046 of the sector image 112 created by themulti-mode curvilinear-array transducer may be configured to be between60-90 degrees, so that the sector image 112 does not display the outeredges of an image having the pronounced artifacts.

Referring to FIG. 11, shown there generally as 1100 is an exampleconfiguration of the transducer elements 850 provided on a multi-modelinear-array transducer 704, in accordance with at least one embodimentof the present invention. Similar to the multi-mode curvilinear-arraytransducer 606, the multi-mode linear-array transducer 704 may beconfigured with a transducer head 650′ including a number of transducerelements 850. A subset 654′ of the transducer elements 850 may beactivated during a second mode of operation. Again, similar to themulti-mode curvilinear-array transducer 606 discussed above, this subset654′ may be any number of the transducer elements 850 available on thetransducer head 650′. The angular spacing 1040′ between successiveultrasound signals 110 may also be similar to that of the multi-modecurvilinear-array transducer 606.

Referring simultaneously to FIG. 1, the transducer element array of atraditional sequential linear-array transducer 104 may have a pitch ofbetween 100-300 microns and a cut width of between 10-150 microns. Themulti-mode linear-array transducer 704 may be configured with atransducer element array having similar dimensions. Similar to themulti-mode curvilinear-array transducer 606 discussed above, in caseswhere there are differences between the configuration of the transducerelement array in the multi-mode linear-array transducer 704 versus thatwhich is in traditional phased-array transducer 102, there may becertain image artifacts that appear more pronounced on the outer edgesof a sector image 112 generated using the second imaging mode of themulti-mode linear-array transducer 704. In some embodiments, the sectorangle 1046′ of the sector image 112 may also be configured to be lessthan 90 degrees (e.g., between 60-90 degrees) so that the sector image112 does not display the outer edges of the image having the pronouncedartifacts.

As noted above, for the multi-mode curvilinear-array transducer 606, thetime delays 802B, 802A, 802C (as shown in FIG. 9) applied to steer theultrasound signals 110 in the second imaging mode may be adjusted tocompensate for the aperture 804D being positioned in a curve rather thana line. For the multi-mode linear-array transducer 704, theseadjustments need not be applied because the transducer elements 805 arenot positioned along a curve.

As shown in various figures herein, the subset 654, 654′ of thetransducer elements 850 that are activated during the second mode ofimaging have been at or near the center portion of the transducerelement array. However, in some alternate embodiments, the subset 654,654′ of transducer elements may be along any portion of the transducerelement array. For example, in some embodiments, the subset 654, 654′ oftransducer elements 850 may be on the left edge or the right edge of thetransducer element array. In some embodiments, the subset 654, 654′ ofthe transducer elements 850 may be selected to be aligned with anexternal marking on the housing of the multi-mode transducers 606, 704discussed herein.

Referring to FIG. 12, shown there generally as 1200 is a functionalblock diagram of an ultrasound machine, in accordance with at least oneembodiment of the present invention. The ultrasound machine 1200 mayinclude a transducer head 650 that may form part of the multi-modecurvilinear-array transducer 606 or the multi-mode linear-arraytransducer 704 discussed above. The transducer head 650 may include atransducer array 1202 with a number of constituent transducer elements850.

A transmitter 1206 may be provided to energize the transducer elements850 to produce the ultrasound signals 110. Another group of transducerelements 850 may then form the receive aperture to convert the receivedultrasound energy into analog electrical signals which are then sentthrough a set of transmit/receive (T/R) switches 1204 to a number ofchannels of echo data. A set of analog-to-digital converters (ADCs) 1208digitises the analog signals from the switches 1204. The digitisedsignals are then sent to a receive beamformer 1212.

Transmitter 1206 and receive beamformer 1212 are operated under thecontrol of a scan controller 1210. Receive beamformer 1212 combines theseparate echo signals from each channel using pre-calculated time delayand weight values that may be stored in a coefficient memory (not shown)to yield a single echo signal which represents the received energy froma particular scanline. Under the direction of the scan controller 1210,the ultrasound machine 1200 generates and processes additional transmitand receive events to produce the multiple scanlines required to form anultrasound image. Ultrasound images are typically made up of 50 to a fewhundred lines. Typically, the number of scanlines of an ultrasound imagegenerated from a sequential transducer may correspond to the number oftransducer elements 850 in the transducer array 1202.

However, when the multi-mode array transducers 606, 704 described hereinare operated in the second mode, the scanlines generated from the subset654, 654′ (as shown in FIGS. 6 and 7) of activated transducer elements850 may not correlate to the number of the transducer elements 850present in the transducer array 1202. Instead, the number of scanlinesmay correspond the configured angular separation 1040, 1040′ of thetransmitted ultrasound signals 110 that generate echo signals which formthe sector image (as shown in FIGS. 10 and 11). In some embodiments, theapparatus and methods described herein may be employed using both SingleLine Acquisition (SLA) and Multi-Line Acquisition (MLA) techniques. Aswill be understood by persons skilled in the art, images generated usingSLA techniques have a single receive scanline for a single transmittedultrasound signal 110 and images generated using MLA techniques havemultiple receive scanlines for a single transmitted ultrasound signal110. This may allow ultrasound systems that employ MLA techniques tohave improved frame rates. In further embodiments, synthetic aperturetechniques may be used in the first imaging mode and/or the secondimaging mode to improve lateral resolution of an ultrasound image.

An ultrasound processor 1214 may be in communication with the receivebeamformer 1212 and applies the necessary processing steps to combinemultiple scanlines from these different transmit events to yield imagedata. The processor 1214 communicates this image data via a data link1215 to a display device 1218. Data link 1215 may include a cable, awireless connection, or the like. Display device 1218 displays theultrasound image to the user. In some embodiments, the display device1218 may not be separate, and instead be provided as an integrated partof the ultrasound machine 1200. In the latter case, the data link 1215may be a data bus or other suitable connector between the processor 1214and the display 1218.

The image mode selector 1216 may receive input to select between thefirst imaging mode and the second imaging mode discussed herein. Theimage mode selector 1216 may be provided in the form of any physical orsoftware-based user interface control. For example, in some embodiments,a user control such as a push button, a graphical user interfacecontrol, or the like may be operated by an ultrasound operator. The datainput selecting the mode of operation may be provided to ultrasoundprocessor 1214 via data link 1215. In turn, the ultrasound processor1214 may provide a configuration signal to controller 1210 to modify theoperation of the transmitter 1206 and receive beamformer 1212 toactivate the transducer array 1202 in accordance with the selectedimaging mode.

The embodiments described herein may be used with ultrasound machines1200 having a variety of different form factors. As illustrated in FIG.12, the transducer head 650 is shown in dotted outline in relation tothe processing components 1220 of the ultrasound machine 1200 toillustrate that it can be coupled thereto via any type of communicationlink 1205. For example, in some embodiments, the transducer may bedetachably coupled to the body of the ultrasound machine 1200 via acable or other suitable wired connection. In some such embodiments, theultrasound machine 1200 may include both the processing components andthe display 1218 and image mode selector 1216 in a unitary body.

In certain embodiments, the transducer head 650 and processingcomponents 1220 may be provided in a single device (e.g., having aunitary body). In such case, the processor 1214 may communicate todisplay 1218 and image mode selector 1214 via a wireless communicationlink. The image mode selector 1216 and display 1218 is shown in dottedoutline to show that they may not form part of the processing components1220 in such embodiments. In some such embodiments, the single devicecontaining the transducer head 650 and processing components 1220 may beprovided as a wireless handheld probe that is configured to communicatewith an external wireless computing device containing a display 1218 andis able to provide functionality for the image mode selector 1216. Insome embodiments, such wireless handheld probe may be provided in a formfactor that has a mass that is less than 4.5 kilograms.

Configuring a single transducer head 650 to operate in multiple imagingmodes as described herein may be desirable in embodiments where thetransducer head 650 and the processing components 1220 are provided in aunitary body because it is not possible to remove the transducer head650 from the body containing the processing components 1220. Put anotherway, configuring the single, non-detachable transducer head 650 tooperate in multiple imaging modes may provide enhanced utility of awireless handheld ultrasound probe.

INTERPRETATION OF TERMS

Unless the context clearly requires otherwise, throughout thedescription and the claims:

-   -   “comprise”, “comprising”, and the like are to be construed in an        inclusive sense, as opposed to an exclusive or exhaustive sense;        that is to say, in the sense of “including, but not limited to”;    -   “connected”, “coupled”, or any variant thereof, means any        connection or coupling, either direct or indirect, between two        or more elements; the coupling or connection between the        elements can be physical, logical, or a combination thereof;    -   “herein”, “above”, “below”, and words of similar import, when        used to describe this specification, shall refer to this        specification as a whole, and not to any particular portions of        this specification;    -   “or”, in reference to a list of two or more items, covers all of        the following interpretations of the word: any of the items in        the list, all of the items in the list, and any combination of        the items in the list;    -   the singular forms “a”, “an”, and “the” also include the meaning        of any appropriate plural forms.

Unless the context clearly requires otherwise, throughout thedescription and the claims:

Words that indicate directions such as “vertical”, “transverse”,“horizontal”, “upward”, “downward”, “forward”, “backward”, “inward”,“outward”, “vertical”, “transverse”, “left”, “right”, “front”, “back”,“top”, “bottom”, “below”, “above”, “under”, and the like, used in thisdescription and any accompanying claims (where present), depend on thespecific orientation of the apparatus described and illustrated. Thesubject matter described herein may assume various alternativeorientations. Accordingly, these directional terms are not strictlydefined and should not be interpreted narrowly.

Embodiments of the invention may be implemented using specificallydesigned hardware, configurable hardware, programmable data processorsconfigured by the provision of software (which may optionally comprise“firmware”) capable of executing on the data processors, special purposecomputers or data processors that are specifically programmed,configured, or constructed to perform one or more steps in a method asexplained in detail herein and/or combinations of two or more of these.Examples of specifically designed hardware are: logic circuits,application-specific integrated circuits (“ASICs”), large scaleintegrated circuits (“LSIs”), very large scale integrated circuits(“VLSIs”), and the like. Examples of configurable hardware are: one ormore programmable logic devices such as programmable array logic(“PALs”), programmable logic arrays (“PLAs”), and field programmablegate arrays (“FPGAs”)). Examples of programmable data processors are:microprocessors, digital signal processors (“DSPs”), embeddedprocessors, graphics processors, math co-processors, general purposecomputers, server computers, cloud computers, mainframe computers,computer workstations, and the like. For example, one or more dataprocessors in a control circuit for a device may implement methods asdescribed herein by executing software instructions in a program memoryaccessible to the processors.

For example, while processes or blocks are presented in a given orderherein, alternative examples may perform routines having steps, oremploy systems having blocks, in a different order, and some processesor blocks may be deleted, moved, added, subdivided, combined, and/ormodified to provide alternative or subcombinations. Each of theseprocesses or blocks may be implemented in a variety of different ways.Also, while processes or blocks are at times shown as being performed inseries, these processes or blocks may instead be performed in parallel,or may be performed at different times.

The invention may also be provided in the form of a program product. Theprogram product may comprise any non-transitory medium which carries aset of computer-readable instructions which, when executed by a dataprocessor (e.g., in a controller and/or ultrasound processor in anultrasound machine), cause the data processor to execute a method of theinvention. Program products according to the invention may be in any ofa wide variety of forms. The program product may comprise, for example,non-transitory media such as magnetic data storage media includingfloppy diskettes, hard disk drives, optical data storage media includingCD ROMs, DVDs, electronic data storage media including ROMs, flash RAM,EPROMs, hardwired or preprogrammed chips (e.g., EEPROM semiconductorchips), nanotechnology memory, or the like. The computer-readablesignals on the program product may optionally be compressed orencrypted.

Where a component (e.g. a software module, processor, assembly, device,circuit, etc.) is referred to above, unless otherwise indicated,reference to that component (including a reference to a “means”) shouldbe interpreted as including as equivalents of that component anycomponent which performs the function of the described component (i.e.,that is functionally equivalent), including components which are notstructurally equivalent to the disclosed structure which performs thefunction in the illustrated exemplary embodiments of the invention.

Specific examples of systems, methods and apparatus have been describedherein for purposes of illustration. These are only examples. Thetechnology provided herein can be applied to systems other than theexample systems described above. Many alterations, modifications,additions, omissions, and permutations are possible within the practiceof this invention. This invention includes variations on describedembodiments that would be apparent to the skilled addressee, includingvariations obtained by: replacing features, elements and/or acts withequivalent features, elements and/or acts; mixing and matching offeatures, elements and/or acts from different embodiments; combiningfeatures, elements and/or acts from embodiments as described herein withfeatures, elements and/or acts of other technology; and/or omittingcombining features, elements and/or acts from described embodiments.

It is therefore intended that the following appended claims and claimshereafter introduced are interpreted to include all such modifications,permutations, additions, omissions, and sub-combinations as mayreasonably be inferred. The scope of the claims should not be limited bythe preferred embodiments set forth in the examples, but should be giventhe broadest interpretation consistent with the description as a whole.

What is claimed is:
 1. An ultrasound imaging method comprising, by anultrasound imaging machine: imaging in a first mode using a sequentialtransducer comprising a plurality of transducer elements, wherein whenimaging in the first mode, sequential groups of adjacent transducerelements of the plurality of transducer elements are pulsed forbeamforming, the beamforming comprising delayed activation of thetransducer elements within each of the groups of adjacent transducerelements, and wherein a same time delay is used to beamform for all thegroups of adjacent transducer elements; and imaging in a second modedifferent from the first mode, wherein when imaging in the second mode,a subset of at least two of the plurality of transducer elements areactivated and the subset of transducer elements is repeatedly pulsed forbeamforming, the beamforming comprising delayed activation of thetransducer elements within the subset of transducer elements, andwherein the beamforming is repeatedly performed using a plurality ofdifferent time delays, so that a plurality of ultrasound signals aresteered from the subset of transducer elements.
 2. The ultrasoundimaging method of claim 1, wherein when imaging in the second mode, anyremaining transducer elements of the plurality of transducer elementsnot part of the subset are inactive.
 3. The ultrasound imaging method ofclaim 1, wherein when imaging in the first mode, the sequential groupsof adjacent transducer elements correspond to respective differentapertures along a head of the sequential transducer; and when imaging inthe second mode, the subset of the plurality of transducer elementscorrespond to a single aperture on the head of the sequentialtransducer.
 4. The ultrasound imaging method of claim 1, wherein thesequential transducer comprises a curvilinear transducer, and whenimaging in the first mode, each of the plurality of ultrasound signalsare projected in a direction orthogonal to the surface of the sequentialtransducer so that a curvilinear image is generated.
 5. The ultrasoundimaging method of claim 1, wherein the sequential transducer comprises alinear transducer, and when imaging in the first mode, each of theplurality of ultrasound signals are projected in a direction orthogonalto the surface of the sequential transducer so that a rectangular imageis generated.
 6. The ultrasound imaging method of claim 1, wherein whenimaging in the second mode, each of the plurality of ultrasound signalsis steered in a respective different direction so that a sector image isgenerated.
 7. The ultrasound imaging method of claim 6, wherein thesector image has a sector angle of 60 to 90 degrees.
 8. The ultrasoundimaging method of claim 6, wherein angular spacing between therespective different directions is between 0.35 to 0.70 degrees.
 9. Theultrasound imaging method of claim 1, wherein the plurality oftransducer elements comprise a pitch spacing between each adjacenttransducer element, and the pitch spacing is between 100 to 400 microns.10. An ultrasound imaging machine, comprising: an ultrasound processor;and a sequential transducer communicably coupled to the ultrasoundprocessor, the sequential transducer comprising a plurality oftransducer elements; wherein the ultrasound imaging machine is: operablein a first imaging mode in which the ultrasound processor pulsessequential groups of adjacent transducer elements of the plurality oftransducer elements for beamforming, the beamforming comprising delayedactivation of the transducer elements within each of the groups ofadjacent transducer elements, and wherein a same time delay is used tobeamform for all the groups of adjacent transducer elements; andoperable in a second imaging mode different from the first imaging mode,and in the second imaging mode, the ultrasound processor repeatedlypulses a subset of at least two of the plurality of transducer elementsfor beamforming, the beamforming comprising delayed activation of thetransducer elements within the subset of transducer elements, andwherein the beamforming is repeatedly performed using a plurality ofdifferent time delays, so that a plurality of ultrasound signals aresteered from the subset of transducer elements.
 11. The ultrasoundimaging machine of claim 10, wherein when imaging in the second mode,any remaining transducer elements of the plurality of transducerelements not part of the subset are inactive.
 12. The ultrasound imagingmachine of claim 10, wherein in the first imaging mode, the sequentialgroups of adjacent transducer elements correspond to respectivedifferent apertures along a head of the sequential transducer; and inthe second imaging mode, the subset of the plurality of transducerelements correspond to a single aperture on the head of the sequentialtransducer.
 13. The ultrasound imaging machine of claim 10, wherein thesequential transducer comprises a curvilinear transducer, and when inthe first imaging mode, each of the plurality of ultrasound signals areprojected in a direction orthogonal to the surface of the sequentialtransducer so that a curvilinear image is generated.
 14. The ultrasoundimaging machine of claim 10, wherein the sequential transducer comprisesa linear transducer, and when in the first imaging mode, each of theplurality of ultrasound signals are projected in a direction orthogonalto the surface of the sequential transducer so that a rectangular imageis generated.
 15. The ultrasound imaging machine of claim 10, whereinwhen in the second imaging mode, each of the plurality of ultrasoundsignals is steered in a respective different direction, so that a sectorimage is generated.
 16. The ultrasound imaging machine of claim 15,wherein the sector image has a sector angle of 60 to 90 degrees.
 17. Theultrasound imaging machine of claim 15, wherein angular spacing betweenthe respective different directions is between 0.35 to 0.70 degrees. 18.The ultrasound imaging machine of claim 10, wherein the plurality oftransducer elements comprise a pitch spacing between each adjacenttransducer element, and the pitch spacing is between 100 to 400 microns.19. The ultrasound imaging machine of claim 10, wherein the sequentialtransducer comprises a housing containing the plurality of transducerelements, and the housing comprises a marking indicating a position ofthe subset of the plurality of transducer elements amongst the pluralityof transducer elements.
 20. A sequential ultrasound transducer, capableof being communicably coupled to an ultrasound processor, the sequentialultrasound transducer comprising: a plurality of transducer elements,wherein when the sequential ultrasound transducer is communicablycoupled to the ultrasound processor, the ultrasound processor isconfigured to: activate the plurality of transducer elements in a firstimaging mode, wherein in the first imaging mode, sequential groups ofadjacent transducer elements of the plurality of transducer elements arepulsed for beamforming, the beamforming comprising delayed activation ofthe transducer elements within each of the groups of adjacent transducerelements, and wherein a same time delay is used to beamform for all thegroups of adjacent transducer elements; and activate a subset of atleast two of the plurality of transducer elements in a second imagingmode different from the first imaging mode, wherein in the secondimaging mode, the subset of transducer elements are repeatedly pulsedfor beamforming, the beamforming comprising delayed activation of thetransducer elements within the subset of transducer elements, andwherein the beamforming is repeatedly performed using a plurality ofdifferent time delays, so that a plurality of ultrasound signals aresteered from the subset of transducer elements.